Human prostate stem and progenitor cells express estrogen receptor (ER)α and ERβ and exhibit proliferative responses to estrogens. In this study, membrane-initiated estrogen signaling was interrogated in human prostate stem/progenitor cells enriched from primary epithelial cultures and stem-like cell lines from benign and cancerous prostates. Subcellular fractionation and proximity ligation assays localized ERα and ERβ to the cell membrane with caveolin-1 interactions. Exposure to 17β-estradiol (E2) for 15 to 60 minutes led to sequential phosphorylation of signaling molecules in MAPK and AKT pathways, IGF1 receptor, epidermal growth factor receptor, and ERα, thus documenting an intact membrane signalosome that activates diverse downstream cascades. Treatment with an E2–dendrimer conjugate or ICI 182,870 validated E2-mediated actions through membrane ERs. Overexpression and knockdown of ERα or ERβ in stem/progenitor cells identified pathway selectivity; ERα preferentially activated AKT, whereas ERβ selectively activated MAPK cascades. Furthermore, prostate cancer stem-like cells expressed only ERβ, and brief E2 exposure activated MAPK but not AKT cascades. A gene subset selectively regulated by nongenomic E2 signaling was identified in normal prostate progenitor cells that includes BGN, FOSB, FOXQ1, and MAF. Membrane-initiated E2 signaling rapidly modified histone methyltransferases, with MLL1 cleavage observed downstream of phosphorylated AKT and EZH2 phosphorylation downstream of MAPK signaling, which may jointly modify histones to permit rapid gene transcription. Taken together, the present findings document ERα and ERβ membrane-initiated signaling in normal and cancerous human prostate stem/progenitor cells with differential engagement of downstream effectors. These signaling pathways influence normal prostate stem/progenitor cell homeostasis and provide novel therapeutic sites to target the elusive prostate cancer stem cell population.

Migraine is the third most prevalent disease worldwide and current therapies provide only partial relief. Greater insight into molecular migraine mechanisms would create novel therapies. Cytoskeletal flexibility is fundamental to neuronal-plasticity and is dependent on microtubule dynamicity. Histone-deacetylase-6 (HDAC6) decreases microtubule dynamics by deacetylating its primary substrate, α-tubulin. We use validated models of chronic migraine to show that HDAC6-inhibition is an effective migraine treatment and reveal an undiscovered cytoarchitectural basis for migraine chronicity. The human migraine trigger, nitroglycerin, produced chronic migraine-associated pain and decreased neurite growth in pain-processing regions, and these were reversed by HDAC6 inhibition.Cortical spreading depression (CSD), a physiological correlate of migraine aura, also caused decreased cortical neurite growth, while administration of HDAC6-inhibitor restored neuronal complexity and decreased CSD. Our results demonstrate that disruptions in neuronal cytoarchitecture are a feature of chronic migraine, and evolving migraine therapies might include agents that restore microtubule stability and neuronal plasticity.

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